The Kodlin Lowering Kit lowers the rear of HD M8 Softail models up to 1 ” (40mm). Plug and Play! The kit is easy to install and does not require shortening of the threaded rod or to send the suspension out for final assembly. It includes new pre-installed bearings and installation instructions. 880-4030 for all M8 Softails WITH pre-load adjuster knob (FLHC/FLHCS Heritage Classic, FXBR/FXBRS Breakout, FLFB/FLFBS Fat Boy, FLSB Sport Glide, FXBS/FXFB Fat Bob, FLDE Deluxe, FXDR 114) 880-4031 for all M8 Softails WITHOUT the pre-load adjuster knob (FXBB Street Bob, FXLR / FXLRS Low Rider / Low Rider S, FLSL Slim, FXST Standard)